The present invention relates to a high-pressure homogenizer with an epicyclic reduction gear unit.
In the treatment of high-pressure fluids (approximately from 150 to 1500 bar), in particular with regard to emulsion micronization applications, stabilization of dispersions and the controlled cellular rupture/break-up of a fluid, apparatuses called homogenizers are frequently used. Said apparatuses generally comprise a pump with pistons that move with alternating motion by means of a crankshaft (mounted on a fixed pump body), are synchronous and mutually offset by an angle of 360°/n, where n is the number of pumping pistons that move and compress the fluid inside the process part of the machine.
In particular, PR99A000045 discloses a homogenizer comprising an adjustable valve (called homogenizing valve), which achieves the forced passage of the fluid to be treated from a high pressure area to a low pressure area, and a transmission apparatus, in turn comprising a high pressure piston pump, an electric motor which drives the pump and a reduction gear unit connected between the motor and pump. Said reduction gear unit is necessary to reduce the rotation speed of the motor (generally about 1500/1800 revolutions per minute) to a speed that is useful for the operation of the pump (about 150/180 revolutions per minute for the crankshaft with pistons). Typically, the reduction gear unit is of the type with parallel axes and achieves a reduction ratio of about 1:5, whereas a further reduction of said rotation speed (about 1:2) is achieved by the means for transmitting motion from the motor to the reduction gear unit, which generally comprise a system of multiple belts with pulleys (large pulley on the reduction gear unit side and small pulley on the motor side).
In the known solutions, the connection between the reduction gear unit, pump and motor is achieved by means of what is called a “pendulum-like” fastening/assembly technique.
In this manner, the reduction gear unit is movable relative to the pump body, as it can rotate around the axis defined by the crankshaft.
The pendulum-like assembly of the reduction gear unit proves convenient during the assembly stage.
However, said technical solution entails some disadvantages, since it introduces undesirable stresses and oscillations into the transmission apparatus.
Such disadvantages are remedied by WO 2008/044253 of the same Applicant by means of an adaptor flange for rigidly fastening a parallel axis reduction gear unit to the fixed body housing the crankshaft so as to inhibit any oscillation of the reduction gear unit relative to the crankshaft, thus achieving a cylindrical coupling between the reduction gear unit and the fixed body, which is coaxial with the crankshaft.
However, when homogenizers of large sizes and powers (>300 kW) are constructed, if only belts or belts with parallel axis reduction gear units were to be used the overall dimensions obtained would be too large to permit transport of the machine. Furthermore, as in the parallel axis reduction gear unit the input axis is parallel to the output axis and not coaxial therewith, unwanted torques are created.
WO 99/47811 discloses a homogenizer comprising a fixed body housing a rotating crankshaft; a motor for driving the crankshaft; a reduction gear unit interconnected between the crankshaft and transmission means.
US 2008/0182699 shows a epicyclic reduction gear unit for a pump having a different use than the present homogenizer and in any case said document does not contain any teaching as to constructing the reduction gear unit integral with the pump. The same considerations also apply for U.S. Pat. No. 2,795,155.
U.S. Pat. No. 6,039,667 likewise refers to an epicyclic reduction gear unit without any external pump to which it may be associated.
GB 2079383A and WO2008/010490A1 disclose epicyclic reduction gear units of the prior art unable to achieve the results of the present invention.
In this context, the technical task at the basis of the present invention is to propose a homogenizer that overcomes the drawbacks of the above-mentioned prior art.